Because the adverse reactions associated with treatment of onchocerciasis, loiasis, and lymphatic filariasis can be severe, systemic, and debilitating the mediators of this posttreatment reaction have been identified and quantified. In the acute phase (first 48 hours) an intracellular Wolbachia endosymbiont appears in the bloostream and is correlated with the presence of the inflmmatory mediators of the posttreatment adverse reactions. Later, the eosinophil plays a major role as do the chemokines associated with eosinophil trafficking. Diagnostic Studies - PCR-based diagnostic strategies have been developed for Loa loa and Strongyloides stercoralis using recently identified repeated sequences. More importantly, a rapid format card test (based on immunochromatography) has been developed and tested; it shows sensitivities and specificities above 90 percent.